Pick and Place Nozzle Adaptor

ABSTRACT

A releasable adaptor is carried on the end of the pick-and-place vacuum nozzle which diffuses and restricts the air flow access of the nozzle to the top surface of an apertured fastener such as a nut while covering the fastener hole. The adaptor allows a standard nozzle to develop sufficient suction to lift the nut/adaptor combination and transport it to its desired target location such as a circuit board. There, the nut is released from the adaptor, which is then lifted by the nozzle and transported back to the supply location. This functionality is achieved by a unique adaptor air valve which the PNP equipment operates both mechanically and through its controlled application of negative air pressure applied to the adaptor by the nozzle.

RELATED APPLICATIONS

This is a non-provisional patent application related to provisionalapplication No. 62/094,243 entitled “Pick and Place Nozzle Adaptor”filed on Dec. 19, 2014, priority from which is hereby claimed.

FIELD OF THE INVENTION

The present invention relates to automated pick-and-place manufacturingassembly machines, which take individual parts from a supply locationand place them into a designated position with other components of agreater assembly. More specifically, it relates to pick-and-placerobotics used in the electronics industry for placing components onto acircuit board.

BACKGROUND OF THE INVENTION

Pick-and-place machines (hereinafter “PNP”) for positioning componentsonto a circuit board have been used for many years. In one such system,a robotic transport arm has a vacuum line and a nozzle at the end thatlifts components from a supply station and delivers them to a specificlocation on a circuit board. To achieve this step, the individualcomponent must have a top surface that will form a vacuum seal with thenozzle tip. Components that have through holes (“apertured components”),such as internally threaded fasteners, present a problem since the holein their top surface is not conducive to drawing a vacuum by a standardnozzle tip. Nozzle tips cannot be custom designed for each differentpart because many differently-shaped components must be delivered by thesame nozzle to the same circuit board in sequence.

To solve this problem, it is known to add a piece of adhesive tape tothe top of the apertured component to seal off the hole. The tapecreates a uniform planar surface with which the nozzle tip cansufficiently vacuum seal so that component can be lifted. However, thissolution is not ideal since it requires an additional sacrificialelement be applied to the apertured component and then later removed.Applying tape adds cost, slows production rates and creates used tapescrap. It is therefore desirable to provide the electronics industry anautomated assembly means that can efficiently handle aperturedcomponents using standard PNP equipment.

SUMMARY OF THE INVENTION

In one preferred embodiment, an adaptor is provided that can be usedwith apertured components, which avoids the need to first temporarilyseal the aperture in the component. The adaptor is releasable andtravels on the end of the PNP nozzle. The adaptor diffuses and restrictsthe air flow access of the nozzle to the top surface of the aperturedcomponent, such as a nut, while covering the central aperture. Theadaptor enables a standard nozzle to develop sufficient suction to liftthe nut/adaptor combination and transport it to its desired locationsuch as a hole in a circuit board. At the target location, the componentis released from the adaptor, which is then lifted by the nozzle andtransported back to the supply location. The nozzle adaptor achievesthis functionality using a unique air valve, which the PNP operates bothmechanically and through its controlled application of air pressureapplied to the adaptor by the PNP nozzle.

In one preferred embodiment, the PNP nozzle adaptor has a body with atop, a bottom, and a central axial bore. The body has a manifold cavity,which is open at the bottom and has a larger diameter than the bore thataccepts the apertured component. A plunger is closely fitted within aninternal shoulder in the bore, which has a reduced diameter. The plungerreciprocates between upwardly retracted and downwardly extendedpositions. An O-ring at the bottom of the plunger captivates the plungerwithin the body and limits its upward movement. An enlarged head at thetop of the plunger limits its downward movement. A recoil spring ispositioned and operative between the underside of the plunger head andthe shoulder in the body to normally bias the plunger in the retractedposition. The plunger has a vacuum chamber that is open at the top ofthe plunger. An extension on the bottom end of the plunger is adapted tocover the hole in the nut when the plunger is extended downward. Atleast one air intake port extends from the vacuum chamber laterally(radially) through the sidewall of the plunger near its bottom end. Theshoulder covers the ports when the plunger is upwardly retracted. Whenthe plunger is downwardly extended, the ports lie beyond the shoulderand are open to the manifold cavity. In this construction, the plungeracts as a slide valve which opens and closes the intake ports. Thus, theplunger can function both as a slide valve and a cover for the hole inthe apertured component.

The spring-biased plunger is moved by the mechanical action of thenozzle against it. When the plunger is pushed downwardly to the extendedposition, the intake ports are open to the manifold cavity so that aircan flow between the cavity and the chamber. In this position, thebottom of the plunger contacts the nut and seals off the hole. Anannular step around the top of a recess at the bottom of the body alsocontacts and seals against the top surface of the apertured component.This construction enables a vacuum connection between the adaptor andthe apertured component. When it is desired to release the component,the vacuum is stopped and the plunger is biased to the retractedposition by the recoil spring as the nozzle is lifted a distance equalto the stroke of the plunger. In the retracted position, the intakeports are closed by the inner wall of the shoulder in the adaptor body.In this position, the vacuum chamber is only open to the PNP vacuumnozzle through the opening at the top of the plunger. In this position,suction can be re-applied to the adaptor, which can then be carried awayby the nozzle with the apertured component left behind.

The operation of one embodiment of the invention may be morespecifically described as follows. At a supply location, with an adaptoralready placed on a nut, the PNP nozzle pushes the plunger downwardlyagainst the biasing force of the recoil spring. This movement continuesuntil the plunger contacts and covers the upper surface of the aperturedcomponent. The plunger valve connects ambient air in fluid communicationwith the top surface of the apertured component. Suction is then appliedand the component is thereby forcefully captured in the lower cavity ofthe adaptor body. The component is then transported with the adaptor bythe PNP to the desired circuit board location. The nut is then releasedfrom the adaptor by stopping nozzle suction. Then, the nozzle is movedupward, which allows the recoil spring to bias the plunger upward to theretracted position to close the valve between the vacuum source and theapertured component. With the valve closed, a vacuum is again drawn onthe adaptor which is then lifted away from the component and back to thesupply location where it is placed on the next component in the supplyreel. The next component can then be taken or the adaptor can bereleased from the nozzle by terminating the suction. The nozzle can thenmove away from the supply reel to transport any other part to thecircuit board.

The advantages of the nozzle adaptor of the present invention areprovided by a simple, self-actuating device. The adaptorsspring-actuated mechanism does not rely upon any motive force other thanthe mechanical force of the PNP nozzle and the negative air pressure itapplies. Other advantages and differences will follow from the foregoingexplanation and the following drawings and description of the invention.The preferred embodiment of the invention will provide one of skill inthe art with a full understanding of what has been invented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top, front perspective of an adaptor in accordance with apreferred embodiment of the invention;

FIGS. 2A and 2B are side-by-side cross-sections showing the adaptor inthe retracted and extended positions, respectively;

FIGS. 3A and 3B are sectional views of the nozzle adaptor interactingwith a reel-supplied, apertured component before and after it isconnected to vacuum pressure;

FIG. 3C is an enlarged fragmentary cross section;

FIGS. 4A and 4B are sectional views of the nozzle adaptor transportingand inserting an apertured component on a circuit board; and,

FIGS. 5A and 5B are sectional views of the nozzle adaptor releasing anapertured component on a circuit board and returning to a supply reel ofadditional apertured components.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A nozzle adaptor in accordance with a preferred embodiment isillustrated in FIGS. 1-5 and is designated generally by referencenumeral 10. The nozzle adaptor 10 generally comprises a mainbody/housing 11, a plunger 13 and a recoil spring 15. With reference tothe orientation shown in FIGS. 1 and 2, the plunger 13 reciprocatesupwardly and downwardly within the housing. The recoil spring 15normally urges the plunger 13 to the retracted position shown in FIG.2A. The plunger 13 is shown in its extended position in FIG. 2B. Itshould be understood that although the main elements of this preferredembodiment are cylindrical, other shapes and sizes may be utilized.

In FIG. 2A, the plunger is held retracted by the spring 15 and the airintake ports are closed by the shoulder 11 d. In FIG. 2B, the plunger 13is in the extended position and the intake ports 20 are open to themanifold cavity 23 (described below). Thus motion of the plunger betweenup and down positions acts as a slide valve which opens and closes theintake ports 20.

The body 11 of the adaptor 10 has a generally-cylindrical shape with anupper portion 11 a and an enlarged-diameter lower portion 11 b. Theupper 11 a and lower 11 b portions transition at an external shoulder 11c and a first internal shoulder 11 d. The inner walls of the body 11define an internal, axial-extending central bore 22 extending entirelythrough the body 11. The central bore 22 has an upper portion 22 a, acentral portion 22 b and a lower portion 22 c defined by the interiorwalls of the upper portion 11 a, first internal shoulder 11 d, and lowerportion 11 b of the body 11, respectively. The lower portion 22 c actsas a manifold cavity and has an enlarged recess 28 formed at the axialend of the lower portion 11 b of the body. The enlarged recess 28 isco-axial with the central bore and forms a second internal shoulder 11e, which engages the top of the apertured component with which thenozzle is designed to be used. Preferably, the shape of the recessmatches the shape of the apertured component so that the nozzle iscentered on the apertured component. In one preferred embodiment, therecess 28 has a cylindrical shape that compliments the shape of theouter surface of a nut.

The plunger 13 has a generally-cylindrical shape with an enlarged head14 a at one end, side walls 14 b, and an end wall 14 c. A central, axialvacuum chamber 17 extends from the head 14 to the end wall 14 c. Aplurality of radially-extending ports 20 are located proximate the endwall 14 c and extend through the side walls 14 b. In the preferredembodiment shown in FIGS. 1-5, the ports 20 are equally spaced at90-degree intervals around the perimeter of the plunger 13. An annularrace 34 is formed in the outer surface of the side walls 14 b proximatethe end wall 14 c. An O-ring 21 is seated in the race 34.

The spring 15 is captivated between the head 14 a and the first internalshoulder 11 d. The plunger 13 is captivated to the body 11 by theenlarged head 14 a at the top and the O-ring seal 21 near the bottom,which abuts the bottom of the first internal shoulder 11 d. The outerdiameter of the side walls 14 b is slightly smaller than but closelyapproximates the inner diameter of body 11 at the inner shoulder 11 d.This close-fitting arrangement controls alignment of the plunger 13within the body 11 as it reciprocates to open or close the ports 20.Referring to FIG. 2A, the ports 20 align with and are occluded by thecentral portion 11 b of the side walls 14 b. Referring to FIG. 2B, asthe plunger 13 moves to the extended position wherein the ports 20 moveinto axial alignment with the lower portion 11 c of the side walls 11.However, since the diameter of the sidewalls at this axial location isgreater than the diameter of the plunger 13, the ports are un-occludedand create a fluid passageway from the manifold cavity 22 c into thecentral vacuum chamber 17.

FIGS. 3a-3d show the interaction between the nozzle adapter 10 and anapertured component 24 on a reel strip 25 of components 24. Referringnow to FIG. 3A, an apertured component 24 such as a nut 24 is deliveredto a home position by an advancing reel strip 25 that holds a row ofsimilar components. The PNP provides motion and vacuum control to astandard lifting nozzle 30, such as shown in FIG. 3B, to remove anapertured component 24 from the reel strip 25 and insert it in the hole33 of a circuit board, such as shown in FIG. 3B.

The adaptor 10 is initially positioned on the first nut 24 on the reel25. In this first step, the plunger 13 is arranged in the retractedposition as shown in greater detail in FIG. 2A. Next, the PNP depressesthe plunger 13 to the extended position shown in FIGS. 2B, 3B and 3C bypushing on the head 14 a against the resistive force of the recoilspring 15. Downward movement of the nozzle 30 is stopped when theapertured component 24 contacts the second internal shoulder 11 e andthe end wall 14 c as seen in FIGS. 3B and 3C. In this position, the topof the apertured component 24 around the hole is covered by the end ofthe plunger 13. The manifold cavity 22 c is also sealed off byengagement of top surface of the component nut 24 with the secondinternal shoulder 11 e. Vacuum pressure is then applied to the vacuumchamber, which also creates an effective vacuum in the manifold cavity22 c since the cavity 22 c is connected in fluid communication with thevacuum chamber 17 through the ports 20 as shown by fluid flow lines inFIG. 2B. The vacuum creates a releasable attachment between thecomponent 24 and the adaptor 10. The vacuum is sufficient to overcomethe force of the recoil spring 15 and the weight of thecomponent/adaptor combination so that the component and adaptor can nowbe lifted by the PNP.

After the component 24 is removed from the reel strip 25, it is carried,as seen in FIG. 4A, and positioned in the receiving hole 33 of thecircuit board 31, as seen in FIG. 4B. After the component 24 is placedon the circuit board 31, the vacuum is halted and the PNP lifts thenozzle 30 a small amount, which allows the plunger 13 to return to theretracted position shown in FIGS. 5a and 2A. In the retracted position,the air intake ports 20 are closed and the vacuum applied to the nut isrelieved by air flow through the unsealed hole in the aperturedcomponent 24. Finally, the vacuum is re-applied to the vacuum chamber 17so that the adaptor nozzle 10 can be lifted away from the component 24and returned to the supply strip 25 as shown in FIG. 5B. The PNP canthen acquire the next component 27 on the reel 25 and repeat theinstallation process.

In an alternative method of installing an apertured component, thenozzle adaptor 10 is left in place on the component 24 after it isplaced in the receiving hole 33 on the circuit board 31. In thisembodiment, a vacuum is not re-applied to the plunger 13 after theplunger is returned to the retracted position. The PNP nozzle is thenmoved away from the component 24 to pick and place another type ofcomponent located elsewhere that does not require the adaptor nozzle 10.

From the foregoing, it should be appreciated that the adaptor 10 for aPNP nozzle eliminates the requirement that apertured parts have asacrificial hole seal. The foregoing is to be considered illustrativeonly of the principles and possible embodiments of the invention.Further, since numerous modifications and changes will be readilyapparent to those skilled in the art, it is not desired to limit theinvention to the exact construction and operation shown and described.Accordingly, suitable modifications and equivalents may be resorted to,all falling within the scope of the invention, which shall be determinedonly by the following claims and their legal equivalents.

1. A nozzle adapter for a vacuum pick-and-place machine, comprising: abody having a top, a bottom and a central axial bore, said body having amanifold cavity open at the bottom of the body of greater lateraldimension than said bore for receiving a part; a plunger slideablyengaged within said bore and reciprocal between upwardly retracted anddownwardly extended positions; a vacuum chamber within said plungerhaving an opening at a top of the plunger; at least one air intake portpassing through a sidewall of the plunger providing fluid communicationbetween the vacuum chamber and the manifold cavity; and wherein saidplunger is reciprocally operative such that the at least one port isopen and in fluid communication between said vacuum chamber and saidmanifold cavity when the plunger is in the downwardly extended positionand said at least one port is closed off from the vacuum chamber by thebody when said plunger is in the upwardly retracted position.
 2. Thedevice of claim 1 further including an extension of the plunger locatedbelow the at least one intake port, said extension lying within themanifold cavity and adapted to cover a hole in said part when saidplunger is in the downwardly extended position.
 3. The device of claim 2further including an outwardly stepped recess of enlarged diameter openat the bottom of the body adapted to receive the part.
 4. The device ofclaim 1 including a spring operative between the plunger and the bodybiasing the plunger to the upwardly retracted position.
 5. The device ofclaim 4 wherein the plunger has a head adapted for substantiallyair-tight engagement with a pick-and-place vacuum nozzle whereby avacuum can be drawn upon the vacuum chamber through said opening at thetop of the plunger.
 6. The device of claim 1 wherein the plunger isclosely fitted within an internal shoulder of the body of reduceddiameter.
 7. The device of claim 6 wherein the at least one intake portis closed by the shoulder when the plunger is in the upwardly retractedposition.
 8. The device of claim 1 wherein the manifold cavity isadapted to receive and releaseably attach a fastener to the body only bya vacuum drawn upon the plunger vacuum chamber.
 9. The device of claim 8wherein the fastener is a nut having a threaded bore.
 10. The device ofclaim 9 wherein a bottom end of the plunger is adapted to engage the nutcovering the bore.
 11. The device of claim 3 further including anannular step around the top of the recess which engages a top surface ofthe part.
 12. The device of claim 1 wherein the vacuum chamber is onlyopen to the surrounding atmosphere through said opening at the top ofthe plunger when said plunger is in the upwardly retracted position. 13.The device of claim 12 further including a seal on the outside of theplunger that abuts an underside of the shoulder when the plunger is inthe upwardly extended position.
 14. The device of claim 13 wherein theseal limits the upward movement of the plunger and captivates theplunger within the body.
 15. The device of claim 4 wherein the spring isa coil spring that surrounds the plunger and lies within the bore of thebody.
 16. The device of claim 8 wherein the manifold cavity has aninternal annular step that is adapted to engage a top surface of thefastener.
 17. The device of claim 4 wherein the spring is operativebetween an internal shoulder of the body of reduced diameter and anunderside of a head of enlarged diameter at a top of the plunger.